Numerous staple extractors have been developed and there are numerous patents covering staple extractors.
Several patents disclose specially configured tips for insertion under a staple bridge in order to remove the staple with a levering action of the tool. (In this application, including the claims, the term “bridge” is used to refer to the portion of a staple joining the two legs of the staple.) For example, U.S. Pat. No. 5,031,881, issued 16 Jul. 1991 to Thurmston; U.S. Pat. No. 3,583,673, issued 8 Jun. 1971 to Poskin; U.S. Pat. No. 4,553,737, issued 19 Nov. 1985 to Yi; U.S. Pat. No. 5,090,663, issued 25 Feb. 1992 to Crutchfield et al.; U.S. Pat. No. 6,308,935, issued 20 Oct. 2001 to Rocheford; and U.S. Pat. No. 6,807,699, issued 26 Oct. 2004 to Michelman.
Other patents disclose staple extractors in which, during use, the bridge of the staple is clamped between two pivotally attached members. For example:    1. U.S. Pat. No. 2,750,148, issued 12 Jun. 1956 to Burbank, discloses a device having a pivotally attached hook and prying end, wherein the hook is intended to latch onto a staple bridge to assist in the insertion of the prying end under the bridge and to retain the bridge on the prying end during extraction.    2. U.S. Pat. No. 4,293,119, issued 6 Oct. 1981 to Diederichs, discloses a device having a lower “jaw” for insertion under the bridge of a staple; an upper “jaw” pivotally connected to the lower jaw and spring biased into an open position opposite the lower jaw; and a handle pivotally connected to the lower jaw and linked to the upper jaw, such that in use a downward prying motion of the handle is intended to cause the lower and upper jaw to close, thus clamping the bridge of the staple during extraction.    3. U.S. Pat. No. 4,575,049, issued 11 Mar. 1986 to Fister, discloses a device having a concave tongue for insertion under the bridge of a staple, an opposed convex clamp and a housing, all pivotally linked, wherein in use, squeezing the handle of the device causes the clamp and tongue to close and lift together relative to the housing (braced against the surface containing the staple) so as to extract the staple.    4. U.S. Pat. No. 5,088,692, issued 18 Feb. 1992 to Weiler discloses a device having a pronged member with a double pronged prying end, and a shank pivotally attached to the pronged member and having an end interposable between the prongs, wherein in use the prongs are inserted under a staple bridge and the shank is pivoted relative to the pronged member so as to interpose the shank end between the prongs, thus deforming the bridge so as to clench it between the shank end and the prongs, thus securing the staple for extraction.
The devices disclosed in these patents suffer from a variety of deficiencies, particularly when considered in light of what is desirable in the removal of staples used in furniture, (such as to secure upholstery to wood members), which include that the staple extractor be useable with staples in confined or awkward locations, that the staple extractor permit the user to remove staples by either a levering action of the staple extractor or a direct pull, as the situation warrants; and that the staple extractor minimally mar adjacent surfaces during the extraction process.